In a long term evolution (LTE) system, two states are defined for a user equipment (UE): an idle state and a connection state. When the UE needs to transmit traffic data, it needs to establish a Radio Resource Control (RRC) connection with a base station, thereby switching from the idle state to the connection state.
In the LET system, the UE can transmit the traffic data only in the connection state, and switching from the idle state to the connection state will generally cause larger signaling overhead. In order to achieve the transmission of the traffic data while reducing the signaling overhead, a third state (i.e., an inactive state) of the UE is introduced in the fifth generation mobile communication technology (5G). In the inactive state, the UE can perform the transmission of the traffic data having smaller packets without entering the connection state.